IPD sale XeMODeX - Experts in Volvo Electronics Free shipping all USA - Experts in Brakes
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy anything with this and it helps MVS!

'99 V70 2.4 NA - O2 sensors battle

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

fszczesniak
Posts: 10
Joined: Fri Nov 15, 2019 3:32 pm
Year and Model: V70 1999
Location: Hamburg
Has thanked: 1 time
Been thanked: 0
Germany
fszczesniak

'99 V70 2.4 NA - O2 sensors battle

Post by fszczesniak » Wed Mar 18, 2020 1:12 pm

Long story short, the fuel efficiency got really high lately - 14L/100km, so i started to dig into it. Just renewed my PCV, btw.

after a short diagnose with OBD Fusion, I noticed that my O2 sensors are not working correctly - S1B1 was stuck on about 0,5V and not reacting properly while driving. STFT's and LTFT's were also to high.

Got a new OEM sensor, installed it yesterday, engine is running smoother and nicer now, but the S1 is still stuck at about 0,5V! S2 post-cat on hot idle runs at about 0,85V....

I started measuring the voltages on the plug with my multimeter and got only 3,8V between battery negative and S! signal+ with the ignition on... what the heck is going on here?

User avatar
misha
Posts: 4186
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
Location: Serbia
Has thanked: 54 times
Been thanked: 114 times
Serbia
misha

Re: '99 V70 2.4 NA - O2 sensors battle

Post by misha » Wed Mar 18, 2020 1:18 pm

14l-15l/100km with automatic transmission in city traffic sounds normal to me.
If it is manual...then around 13l/100km.

I guess that it is a 20v car.

Did you removed negative battery cable for 10-15min after o2 sensor replacement...in order to reset ECU and fuel trims?
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

fszczesniak
Posts: 10
Joined: Fri Nov 15, 2019 3:32 pm
Year and Model: V70 1999
Location: Hamburg
Has thanked: 1 time
Been thanked: 0
Germany
fszczesniak

Re: '99 V70 2.4 NA - O2 sensors battle

Post by fszczesniak » Wed Mar 18, 2020 1:50 pm

Heh, it used to be around 11/100 :-) now even a very calm highway trip is not going under 10...
Yes, I did the reset procedure. Actually, during the lambda sensor replacement, the battery was disconnected the whole time.

P.s. yes, it's a 20v engine, non turbo, with ETM

User avatar
misha
Posts: 4186
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
Location: Serbia
Has thanked: 54 times
Been thanked: 114 times
Serbia
misha

Re: '99 V70 2.4 NA - O2 sensors battle

Post by misha » Wed Mar 18, 2020 2:48 pm

At highway speeds 120-140km/h it should be from 8.5l to 10l/100km.

*With automatic transmission

You mentioned that you replaced pcv system....could be that you forgot to connect some of vacuum hoses....creating a vacuum leak.
Or worst....intake manifold gasket not seated properly.

Did high consumption appeared right after pcv job?
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

fszczesniak
Posts: 10
Joined: Fri Nov 15, 2019 3:32 pm
Year and Model: V70 1999
Location: Hamburg
Has thanked: 1 time
Been thanked: 0
Germany
fszczesniak

Re: '99 V70 2.4 NA - O2 sensors battle

Post by fszczesniak » Wed Mar 18, 2020 3:16 pm

I checked everything several times - was not my first pcv job :-) definitely vacuum hoses coming out from the intake manifold are in need of replacing, obd2 shows about 32kpa manifold pressure (don't know the specs). Planning also to smoke test the air intake, vacuums and exhaust in the nearest future

User avatar
misha
Posts: 4186
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
Location: Serbia
Has thanked: 54 times
Been thanked: 114 times
Serbia
misha

Re: '99 V70 2.4 NA - O2 sensors battle

Post by misha » Wed Mar 18, 2020 4:41 pm

What scan tool do you use for the car?
If it's some kind of android app and not VIDA,it can't be trusted.
In what shape is flexi pipe between exhaust manifold and cat?
If it's leaking,o2 sensors will report fault.
Also ...any exhaust leak in between exhaust manifold up to rear o2 will report fault and o2 sensors will not doing their job.

From '99 these cars use Denso management.
Is replacement o2 also Denso?
Bosch will not work on '99 and after.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

fszczesniak
Posts: 10
Joined: Fri Nov 15, 2019 3:32 pm
Year and Model: V70 1999
Location: Hamburg
Has thanked: 1 time
Been thanked: 0
Germany
fszczesniak

Re: '99 V70 2.4 NA - O2 sensors battle

Post by fszczesniak » Wed Mar 18, 2020 11:27 pm

Unfortunately it's not Vida, don't have access to that. I use obd fusion with elm Bluetooth adapter. Exhaust is to be smoke tested, because visually everything looks fine. Yes, it's a Denso sensor, OEM.

fszczesniak
Posts: 10
Joined: Fri Nov 15, 2019 3:32 pm
Year and Model: V70 1999
Location: Hamburg
Has thanked: 1 time
Been thanked: 0
Germany
fszczesniak

Re: '99 V70 2.4 NA - O2 sensors battle

Post by fszczesniak » Thu Mar 19, 2020 9:04 am

What is the actual way to test if lambda is getting enough voltage? I was thinking that you purely turn the ignition on, probe the signal plus (blue) when lambda connected, check voltage on the multimeter between signal + and battery negative... shows only 3,8V! tried also the same procedure on S2 sensor and there was nothing

User avatar
abscate
MVS Moderator
Posts: 20460
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 285 times
Been thanked: 898 times
Trinidad & Tobago
abscate

Re: '99 V70 2.4 NA - O2 sensors battle

Post by abscate » Thu Mar 19, 2020 9:32 am

Its a heated OXS so there are two circuits to check - both the heater circuit and the sensor circuit.
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

fszczesniak
Posts: 10
Joined: Fri Nov 15, 2019 3:32 pm
Year and Model: V70 1999
Location: Hamburg
Has thanked: 1 time
Been thanked: 0
Germany
fszczesniak

Re: '99 V70 2.4 NA - O2 sensors battle

Post by fszczesniak » Thu Mar 19, 2020 9:56 am

Yep, 4 wires (black black - heating, white ground, blue signal +). Checked heating circuit, 2 ohms, perfectly healthy (it's new after all). How do I check the signal circuit? What to probe and how?

Post Reply
  • Similar Topics
    Replies
    Views
    Last post